Medical electrical lead connector ring

ABSTRACT

A medical electrical device that includes an elongated body extending from a proximal end to a distal end having an inner surface forming an elongated body lumen, a conductor extending through the elongated body lumen, and an electrode positioned along the distal end of the elongated body and electrically coupled to a distal end of the conductor. A connector ring is coupled to a proximal end of the elongated body and electrically coupled to a proximal end of the conductor, and includes an inner surface forming a connector ring lumen extending along the connector ring. A first flange extends from the inner surface to a first flange distal end and forms a conductor channel extending along the inner lumen to position the conductor within the connector ring and to form the electrical coupling of the connector ring and the proximal end of the conductor.

TECHNICAL FIELD

The invention relates to implantable medical devices, and, moreparticularly, to configurations of implantable medical lead connectors.

BACKGROUND

In the medical field, implantable medical leads are used with a widevariety of therapeutic or monitoring devices. For example, implantableleads are commonly used to form part of implantable cardiac pacemakersystems that provide therapeutic stimulation to the heart by sensingelectrical activity of the heart and delivering pacing, cardioversion,or defibrillation pulses via electrodes disposed on the leads, typicallynear the distal ends of the leads. Electrodes or sensors carried by thelead are generally coupled to a conductor extending to a proximalconnector assembly for facilitating electrical coupling of theelectrodes or sensors to a therapy delivery or monitoring device. Anumber of challenges exist with respect to such medical leads. Asimplantable medical device technology continues to be downsized and moreadvanced therapeutic techniques are developed, new lead arrangements arerequired. As such, new configurations for electrically coupling anelectrode or other sensor carried by a lead to an associated monitoringor therapy delivery device are needed. In particular, electricalcoupling configurations are needed that are reliable and can bemanufactured in a cost-effective manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and features of the present invention will be readilyappreciated as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings, in which like reference numerals designate likeparts throughout the figures thereof and wherein:

FIG. 1 is a plan view of a medical electrical device according to anembodiment of the present invention;

FIG. 2 is an end view of a connector ring according to an embodiment ofthe present invention included in the medical electrical device of FIG.1;

FIG. 3 is a side, cut-away view of a connector ring according to anembodiment of the present invention;

FIG. 4 is a side cut-away view of a connector ring according to anembodiment of the present invention;

FIG. 5 is an end view of a connector ring according to an embodiment ofthe present invention;

FIG. 6 is a side view of the connecter ring of FIG. 5;

FIG. 7A is an end view of a connector ring according to an embodiment ofthe present invention;

FIG. 7B, is an end view of a connector ring according to an embodimentof the present invention;

FIG. 8 is an end view of a connector ring of a medical electrical deviceaccording to an embodiment of the present invention; and

FIG. 9 is a flow chart of a method for manufacturing a medicalelectrical device according to an embodiment of the present invention.

DETAILED DESCRIPTION

The following detailed description provides a practical illustration forimplementing various embodiments of the invention and is not intended tolimit the scope, applicability, or configuration of the invention in anyway.

FIG. 1 is a plan view of a medical electrical device according to anembodiment of the present invention. As illustrated in FIG. 1, a medicalelectrical device according to an embodiment of the present inventionincludes a lead 10 embodied as a cardiac pacing lead having electrodesthat can be used for sensing cardiac electrogram signals and deliveringelectrical stimulation pulses to myocardial tissue for pacing,cardioverting or defibrillating the heart. Lead 10 includes an elongatedlead body 12 having a proximal end 14 and a distal end 16. Lead 10 isprovided with a distal tip electrode 18 located at or near distal end 16of lead body 12, a ring electrode 20 located proximal to tip electrode18, and two coil electrodes 22 and 24. Distal tip electrode 18 and ringelectrode 20 are commonly used for pacing and sensing the heart. Coilelectrodes 22 and 24 are commonly used for delivering high-voltagecardioversion and defibrillation pulses to the heart. While a particularelectrode arrangement is shown in FIG. 1, it is recognized that variousembodiments of the invention may include a variety of lead types,including neuromuscular stimulation leads, monitoring leads, or anyother medical electrical leads. Such leads may be provided with avariety of electrode arrangements, which may include one or moreelectrodes included on lead body 12. Furthermore, different types ofelectrodes, such as an active fixation electrode, or any other electrodeor sensor known for use with implantable medical leads may be includedon lead 10.

Lead body 12 includes at least one lumen 13 through which insulatedconductors 15 extend between each of the respective electrodes 18, 20,22, and 24 and a proximal connector assembly 28 located at proximal bodyend 14. Connector assembly 28 is adapted for connection to a connectorbore included in an associated medical device, such as a pacemaker orneurostimulator device. Such connector assembly configurations formating with a medical device connector bore are known in the art.

Connector assembly 28 includes a pin connector 30 and three ringconnectors 32, 34 and 36. Each of pin connector 30 and ring connectors32, 34 and 36 are coupled to a respective conductor extending to one oftip electrode 18, ring electrode 20 and coil electrodes 22 and 24 suchthat each electrode is electrically coupled to one of pin connector 30or ring connectors 32, 34 and 36 but remain electrically isolated fromeach other. Upon proper insertion of connector assembly 28 into anassociated medical device connector bore, electrodes 18, 20, 22, and 24become electrically coupled to the medical device circuitry via therespective pin connector 30 and ring connectors 32, 34, and 36 andassociated insulated conductors extending between the connectors and theelectrodes.

Connector assembly 28 includes an insulative sheath 35 mounted aroundconnector pin 30 and terminating prior to a proximal end 31 of connectorpin 30. Connector rings 32, 34, and 36 are mounted on insulative sheath35 and are thereby insulated from connector pin 30. Connector rings 32,34 and 36 are insulated from each other by intervening insulativesegments 38, which may include sealing rings 39 for forming fluid-tightseals with a corresponding connector bore between each of connectorrings 32, 34 and 36. It is recognized that connector assembly 28 may beembodied in a variety of ways, including varying configurations ofinsulative members for supporting and insulating the required number ofconnectors needed to electrically couple electrodes or sensors carriedby the lead to an associated medical device. Examples of arrangements ofa connector pin and one or more connector rings on a connector assemblyare generally disclosed in U.S. Pat. Nos. 4,951,687 issued to Ufford etal., and 5,007,435 issued to Doan et al.

FIG. 2 is an end view of a connector ring according to an embodiment ofthe present invention included in the medical electrical device ofFIG. 1. Connector ring 32 is a generally cylindrical member having anouter diameter 40 and inner diameter 42. Connector ring 32 is formedwith a conductor channel 44 extending longitudinally along the innerdiameter 42 of connector ring 32. Conductor channel 44 is provided forreceiving an uninsulated proximal portion of a conductor. The term“channel” as used herein refers to a passage having one open side, suchas a generally “U”-shaped or “C”-shaped passage, in contrast to a fullyenclosed or annular passage, such as a generally “O”-shaped or“D”-shaped passage. In FIG. 2, conductor channel is shown as a generally“U”-shaped passage formed by two flanges 46 and 48 adapted to be crimpedclosed around a conductor extending through conductor channel lumen 50.Thus the conductor channel 44 is provided initially as an open passagehaving open side 49 formed by flanges 46 and 48. The closed side 52 ofchannel 44 can be formed as a generally curved surface as shown in FIG.2. Conductor channel lumen 50 is sized to approximately match the outerdiameter of a conductor. The proximal portion of the conductor can bepositioned in conductor channel 44 by either threading the conductorinto conductor channel lumen 50 or by threading the conductor throughlumen 82 of connector ring 32 then dropping the conductor down intoconductor channel 44 through open side 49.

Connector ring 32 is fabricated from a conductive material, such asMP35N, titanium, or stainless steel. Connector ring 32 is formed duringa machining process that includes machining the inner diameter 42 fromround stock. In one method, a pilot hole is machined so that anelectrical discharge machining wire burner can be threaded through theround stock. The wire burner is then used to form inner diameter 42 andconductor channel 44 in one machining process. The use of EDM wireburner for machining conductor channel 44 reduces the number ofmachining steps required to machine connector rings as compared to pastpractice, which used EDM hole popper methods. The EDM wire burner stepfor forming conductor channel 44 can be performed on multiple, stackedconnector ring piece parts to further reducing manufacturing time.

FIG. 3 is a side, cut-away view of a connector ring according to anembodiment of the present invention. Conductor channel 44 is shownextending longitudinally along substantially the entire length ofconnector ring 32. In alternative embodiments, conductor channel 44 mayextend along the inner diameter 42 of connector ring 32 for any portionof the length of connector ring 32. Connector ring 32 may be providedwith a contoured outer diameter 41 to accommodate outer insulationsheaths used in assembling a lead connector.

FIG. 4 is a side cut-away view of a connector ring according to anembodiment of the present invention. As illustrated in FIG. 4, accordingto an embodiment of the present invention, flange 46 of conductorchannel 44 may be formed to include chamfered ends 54 and 56. Similarly,flange 48, not seen in the cut away view of FIG. 4, would also be formedto include chamfered ends similar to ends 54 and 56 of flange 46. In amanufacturing process that involves threading the proximal end of aconductor into conductor channel lumen 50, the threading step may bemore readily performed when ends 54 and 56 are chamfered since the endopenings 51 and 53 to conductor channel lumen 50 will have a largercross-sectional area than when distal ends of the flanges extendstraight up as shown in FIG. 3.

A conductor may be threaded into lumen 50 through either conductorchannel end opening 51 or 53. As shown in FIGS. 3 and 4, connector ring32 provided as a piece part with identically machined ends does not havea designated proximal or distal end. In FIG. 4, flange 46 is providedwith chamfered ends 54 and 56 at both end openings 51 and 53. During anassembly process, which may be manual or automated, the connector ring32 can be oriented in either direction when a conductor is threaded intoeither end opening 51 or 53 of conductor channel 44. In particular,automated assembly of a conductor onto connector ring 32 is facilitatedby providing connector ring 32 with identically machined ends 51 and 53.It is recognized, however, that in other embodiments flanges 46 and 48can be provided with chamfered ends at only one end opening, 51 or 53.During assembly, the connector ring would need to be properly orientedfor a conductor to be threaded into the chamfered end 51 or 53.

FIG. 5 is an end view of a connector ring according to an embodiment ofthe present invention. As illustrated in FIG. 5, according to anembodiment of the present invention, a connector ring 80 is formed asdescribed above, with a conductor 60 positioned to extend through lumen50 of conductor channel 44. Conductor 60 is shown as a cable conductor,however, connector ring sub-assembly 80 may be formed using otherconductor types, such as a wire, stranded, bundled, or coiled conductor.A crimping tool 70 is pressed down over conductor channel 44 to advanceflanges 46 and 48 together such that a distal end 72 of flange 46 idpositioned adjacent to or engaged against a distal end 74 of flange 48to close formerly open side 49 (shown in FIG. 2). Conductor 60 becomesenclosed within conductor channel lumen 50 such that conductor 60 andconnector ring 40 are electrically and mechanically coupled.

Crimping tool 70 is an elongated tool that can be inserted throughconnector ring lumen 82. Crimping tool 70 is provided with a crimpingnotch 76 that extends along crimping tool 70 for a length correspondingto the length of conductor channel 44. Crimping notch 76 is sized suchthat when crimping tool 70 is pressed down over conductor channel 44,flanges 46 and 48 will be crimped together within notch 76 along theentire length of conductor channel 44. A mechanical and electrical crimpjoint between conductor ring 32 and conductor 60 is thereby formed,extending approximately the entire length of conductor channel 44, whichhas been shown to extend approximately the entire length of connectorring 32. It is expected that by providing a crimp joint extending theentire length of connector ring 32, a reliable mechanical and electricalcoupling between connector ring 32 and conductor 60 can be formed whichis capable of withstanding a higher tensile force than a crimp jointextending along only a portion of connector ring 32. However, dependingon the application, a crimp joint that extends only a portion of thelength of connector ring 32 may also provide adequate tensile strengthfor acceptable lead reliability.

After crimping conductor channel 44 around conductor 60, inspection ofthe crimp joint is performed. The crimp joint is readily verified byinspecting if distal ends 72 and 74 meet along the entire length ofconductor channel 44.

FIG. 6 is a side view of the connecter ring of FIG. 5. Crimping tool 70may be inserted into lumen 82 of connector ring 32 from either end 84 or86 for crimping conductor channel 44 around conductor 60. The proximalportion of conductor 60 that extends through lumen 50 of conductorchannel 44 is stripped of insulation 64. Connector ring 80 can beutilized in manufacturing a medical electrical lead.

FIG. 7A is an end view of a connector ring according to an embodiment ofthe present invention. As illustrated in FIG. 7A, according to anembodiment of the present invention, a connector ring 100 is providedwith a conductor channel 102 having a generally “C”-shaped cross-sectionwith open side 106, and extending along connector ring inner surface101. A flange 104 forms a conductor channel lumen 108 through which aconductor 110 is threaded. As shown in FIG. 7B, an end 105 of flange 104is advanced toward inner surface 101 to close open side 106, therebyenclosing conductor 110 within lumen 108 and forming a mechanical andelectrical coupling between connector ring 100 and conductor 110.

FIG. 8 is an end view of a connector ring of a medical electrical deviceaccording to an embodiment of the present invention. Connector ring 32of the embodiment of FIG. 8 is shown having a generally “U”-shapedconductor channel 44 adapted for crimping around a conductor extendingthrough conductor channel lumen 50. In this embodiment, flanges 46 and48 are provided with beveled distal ends 120 and 122, respectively. Thedistal ends 120 and 122 may be provided as rounded, beveled, canted orotherwise modified tips to promote complete and stable closure of openside 49 of conductor channel 44 after crimping. In particular, whenconnector ring 32 is fabricated from Titanium, beveled distal ends 120and 122 promote a more reliable crimp joint.

FIG. 9 is a flow chart of a method for manufacturing a medicalelectrical device according to an embodiment of the present invention.At step 202, fabrication of a connector ring is initiated, includingmachining the inner diameter and outer diameter contours of theconnector ring from solid, round stock of a selected, conductive metalmaterial. At step 204, partially machined connector rings can be stackedfor machining the conductor channel into multiple connector ringssimultaneously at subsequent step 206. At step 206, the conductorchannel is machined on the inner diameter of the connector ring using anEDM wire burner method.

After completion of connector ring fabrication, a connector ringsub-assembly is assembled. At step 208, a proximal, uninsulated portionof a conductor is inserted through the lumen of the conductor channel.This insertion step may be performed by threading the conductor throughan open end of the conductor channel lumen or by threading the conductorthrough an open end of the connector ring lumen then dropping theconductor down into the conductor channel through the open side of theconductor channel.

After inserting the conductor in the conductor channel, a crimping toolis used to crimp the conductor channel to close the open side of theconductor channel at step 210. The resulting crimp joint formed betweenthe conductor and the conductor channel provides mechanical andelectrical coupling between the connector ring and the conductor. Theconnector ring sub-assembly is then ready to use in assembling a leadconnector assembly at step 212. The lead connector assembly can then beused in assembling a medical electrical lead at step 214.

Thus, a connector ring and associated methods for assembling a connectorring sub-assembly, a connector assembly and a medical electrical leadincluding the connector ring, have been presented in the foregoingdescription with reference to specific embodiments. It is appreciatedthat various modifications to the referenced embodiments may be madewithout departing from the scope of the invention as set forth in thefollowing claims.

1. A medical electrical device, comprising: an elongated body extendingfrom a proximal end to a distal end having an inner surface forming anelongated body lumen; a conductor extending through the elongated bodylumen, the conductor having a proximal end and a distal end; anelectrode positioned along the distal end of the elongated body andelectrically coupled to the distal end of the conductor; a connectorring coupled to the proximal end of the elongated body and electricallycoupled to the proximal end of the conductor, the connector ringincluding an inner surface forming a connector ring lumen extendingalong the connector ring; and a first flange extending from the innersurface to a first flange distal end and forming a conductor channelextending along the inner lumen to position the conductor within theconnector ring and to form the electrical coupling of the connector ringand the proximal end of the conductor.
 2. The device of claim 1, furthercomprising a second flange extending from the inner surface of theconnector ring to a second flange distal end engaged against the firstflange distal end, wherein the conductor channel is formed by the firstflange and the second flange.
 3. The device of claim 2, wherein thefirst flange distal end is spaced from the second flange distal endprior to the conductor being positioned within the conductor channel andthe first flange distal end is advanced toward the second flange distalend subsequent to the conductor being positioned within the conductorchannel.
 4. The device of claim 1, wherein the conductor channel extendsthe entire length of the connector ring.
 5. The device of claim 1,wherein the first flange distal end is spaced from the inner surfaceprior to the conductor being positioned within the conductor channel andthe first flange distal end is advanced toward the inner surfacesubsequent to the conductor being positioned within the conductorchannel.
 6. The device of claim 1, wherein the first flange distal endis chamfered.
 7. The device of claim 2, wherein the first flange distalend and the second flange distal end are chamfered.
 8. The device ofclaim 3, wherein the first flange distal end and the second flangedistal end are formed to generate a crimp joint between the first flangedistal end and the second flange distal end.
 9. The device of claim 3,further comprising a tool having a notch for receiving to the firstflange distal end and the second flange distal end to advance the firstflange distal end toward the second flange distal end.
 10. A connectorring of a medical electrical device, comprising: an inner surfaceforming a connector ring lumen extending along the connector ring; and afirst flange extending from the inner surface to a first flange distalend and forming a conductor channel extending along the inner lumen toposition a conductor within the connector ring and to electricallycouple the connector ring and the conductor.
 11. The connector ring ofclaim 10, further comprising a second flange extending from the innersurface of the connector ring to a second flange distal end engagedagainst the first flange distal end, wherein the conductor channel isformed by the first flange and the second flange.
 12. The connector ringof claim 11, wherein the first flange distal end is spaced from thesecond flange distal end prior to the conductor being positioned withinthe conductor channel and the first flange distal end is advanced towardthe second flange distal end subsequent to the conductor beingpositioned within the conductor channel.
 13. The connector ring of claim10, wherein the conductor channel extends the entire length of theconnector ring.
 14. The connector ring of claim 10, wherein the firstflange distal end is spaced from the inner surface prior to theconductor being positioned within the conductor channel and the firstflange distal end is advanced toward the inner surface subsequent to theconductor being positioned within the conductor channel.
 15. Theconnector ring of claim 10, wherein the first flange distal end ischamfered.
 16. The connector ring of claim 11, wherein the first flangedistal end and the second flange distal end are chamfered.
 17. Theconnector ring of claim 12, wherein the first flange distal end and thesecond flange distal end are formed to generate a crimp joint betweenthe first flange distal end and the second flange distal end.
 18. Amethod of forming a medical electrical device, comprising: machining aninner surface of a connector ring to form an inner lumen having a firstflange extending from the inner surface; positioning a conductor withinthe connector ring; and advancing a first distal end of the first flangeto form a conductor channel to fixedly position the conductor withinconnector ring and to electrically couple the connector ring and theconductor.
 19. The method of claim 18, further comprising advancing asecond distal end of a second flange extending from the inner surface tofixedly engage the first distal end and the second distal end to formthe conductor channel.
 20. The method of claim 18, wherein the firstdistal end is advanced to be engaged against the inner surfacesubsequent to the positioning of the conductor within the connectorring.